Last reviewed 2026-04-22 · How we verify

Kaletra + Current Dual NRTI Backbone

Kaletra is a protease inhibitor combination that blocks HIV protease to prevent viral replication, used as part of a three-drug antiretroviral regimen with two nucleoside reverse transcriptase inhibitors.

Kaletra is a protease inhibitor combination that blocks HIV protease to prevent viral replication, used as part of a three-drug antiretroviral regimen with two nucleoside reverse transcriptase inhibitors. Used for HIV-1 infection in treatment-naïve and treatment-experienced patients (as part of combination antiretroviral therapy).

At a glance

Mechanism of action

Kaletra contains lopinavir and ritonavir; lopinavir inhibits HIV protease, preventing the cleavage of viral polyproteins necessary for infectious particle maturation, while ritonavir acts as a pharmacokinetic booster by inhibiting cytochrome P450 metabolism. When combined with a dual NRTI backbone (typically two nucleoside reverse transcriptase inhibitors), this creates a potent three-drug antiretroviral therapy regimen that targets multiple steps of the HIV replication cycle.

Approved indications

• HIV-1 infection in treatment-naïve and treatment-experienced patients (as part of combination antiretroviral therapy)

Common side effects

• Diarrhea
• Nausea
• Abdominal pain
• Headache
• Lipid elevation (hypertriglyceridemia, hypercholesterolemia)
• Hepatotoxicity

Key clinical trials

• A Research Study to See if a Change in Therapy for HIV Infection Can Improve the Immune Response to Treatment (PHASE4)

Primary sources

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